Well drilling and completion composition

ABSTRACT

A well drilling and completion fluid having a potassium salt of a copolymer of (a) acrylic acid, or an α-substituted acrylic acid and (b) acrylate ester having the general formula CH 2  ═CH--COOR where R is an alkyl or hydroxyalkyl having 1 to 4 carbon atoms and substituted R groups; and an accelerator catalyst composed of water, KOH, lignite, sulfonated polystyrene, and, optionally, a vinylsulfonate/vinylamide polymer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a new and improved drilling fluidcomposition. More specifically, the present invention provides a new andimproved well drilling and completion composition which when added todrilling mud prevents flocculation of drilled solids whilesimultaneously controls overall fluid rheology.

2. Description of the Prior Art

The value of potassium electrolytes for the inhibition of bentoniteswelling in drilling fluids has been recognized since the late 1940's.It has been pointed out that potassium ions have a strengthening effectupon clay formations and that the potassium ions fit into the crystalstructure of clay surfaces in such a manner as to not dissociate andcreate dispersive action among clay particles. The effectiveness of thepotassium ion in limiting the peptization of clays has been shown andthe effectiveness of potassium in combating the problems encounteredwhile drilling through sensitive shale formations has been presented.

Although both potassium and sodium are alkali of similar atomicstructure, their properties in colloidal systems have long been noted tobe strikingly dissimilar. The majority of ions have an effectivediameter much larger in water because of hydration and polorizationeffects; however, the monatonic ions of potassium, rubidium, and cesiumare non-hydrated in water solution.

The potassium ion, the largest of the common ions in crystallinesilicates does not change its volume when placed in solution and istherefore only one-third as voluminous as the sodium ion in solution.Inasmuch as adsorption is in inverse ratio to a power of the volume, thepotassium ion is much more strongly absorbed on clays than is sodium.The sodium character of sea water in comparison with the potassiumcharacter of sedimentary rocks is due to this strong preferentialadsorption of potassium by clays.

It is well known that under metamorphic conditions of temperature andpressure montmorillonite (bentonite) will be converted to illite ifpotassium is present. It has been shown, however, that this diageneticmodification can be initiated during the flocculation and settling ofbentonitic sediments in sea water.

It is well documented in the literature that the potassium ion, becauseof its dimensional characteristics in solution will fit into the holesin the oxygen not of silicate surfaces. Because of this, it is attractedstrongly to crystal lattice structure of clay surfaces and unlike thehydrated sodium ion, it is not free to dissociate and form a dispersiveelectrokinetic double layer. Adsorbed potassium ions thus act to inhibitthe spontaneous dispersion of clays into water. It has been shown thatthe potassium ion is two (2) or three (3) times more effective inflocculating clay suspensions than it is the sodium ion.

The accumulation of evidence, including the fact that potassium ions arepreferentially adsorbed by clays, even in the presence of sodium ions,establishes the potassium ion as a highly desirable cation to beemployed in drilling fluid design to stabilize the bore hole.

It has been established that 3% to 5% of KCl solution (10 to 17lbs./bbl.) must be maintained to control hydration and osmotic action insensitive shale formation. A 15% KCl solution (50 lbs./bbl.) willinhibit the chemical dispersion of plastic bentonite masses and willconvert calcium and sodium clays to potassium clays provided that asufficient amount of time is allowed. However, the use of KCl iscorrosive, costly and generally not reliably effective in normaldrilling operations because there is not enough time for the conversionof the calcium and sodium clay to potassium clays.

U.S. Pat. No. 4,000,076 by Bodine, et al, teaches a phosphate added to adrilling mud containing potassium chloride to reduce corrosiveness. U.S.Pat. Nos. 3,079,334 and 3,079,335 to Clem discloses the use ofwater-soluble leonardite in combination with a water-solublepolyphosphate to provide drilling fluids of relatively low gel strengthand viscosity which are effective in preventing hydration and swellingof native clays. Cates in U.S. Pat. No. 4,404,108 teaches reactinglignite and tannin together with sodium sulfite, paraformaldehyde andsodium hydroxide in water to give a reaction product suitable for use asa drilling fluid additive. U.S. Pat. No. 3,766,229 to Turner, et al,presents a dispersing agent and/or fluid loss control agent for drillingfluids obtained by employing sulfonated lignite and/or sulfonated humicacid wherein the cation for these salts are selected from alkali metals,alkaline earth metals and various elements having atomic numbers 57through 71. U.S. Pat. No. 4,033,893 by Mondshine discloses a drillingfluid consisting essentially of a suspension of clay, lime, and alignitic material in an aqueous phase.

What is needed and what has been invented is an improved, sodium freedrilling fluid which prevents flocculation of drilled solids whilesimultaneously controlling overall fluid rheology. The standards of themud systems for the past 30 years have been the dispersed mud systemscomprising primarily lignosulfonates or lignite with a heavy metal, suchas chrome or bichromates, to give these systems stability in controllingmud rheology. These systems have limitations of temperatures between285° F. and 300° F. in controlling filtration and rheologysimultaneously. In chemistry, this would be described as anelectrochemical system.

The drilling fluid system of this invention is a deflocculating system,sodium free, allowing to control mud rheology and filtrationsimultaneously. Chemically, the improved system of this invention may beclassed as a chemisorption process of a non-encapsulating polymer whichfunctions as an uncoiled polymer and allows control of rheology andfiltration without regard to calcium or chlorides levels or temperaturesup to 500° F. as long as the ingredients of the system are induced inaccordance to the concentration of calcium and chloride or to the degreeof temperature encountered while drilling the borehole to accommodatedesired rheology relative to mud density and/or operators' demands andfor filtration control desired.

SUMMARY OF THE INVENTION

The present invention accomplishes its desired objects by broadlyproviding a well drilling and completion composition having a potassiumsalt of a copolymer of a first compound with a formula CH₂ ═CR₁ --COOHwherein R₁ is selected from the group consisting of H, and an alkylhaving 1 to 4 carbon atoms, and a second compound having a formula CH₂═CH--COOR₂ wherein R₂ is selected from the group consisting of an alkylradical and a hydroxyalkyl radical wherein the alkyl and hydroxy alkyleach have 1 to 4 carbon atoms. The well drilling and completioncomposition of this invention also has an accelerator catalyst whichincludes water, KOH, lignite, sulfonated polystyrene, and avinylsulfonate/vinylamide copolymer if the temperature of the system isabove 285° F.

Therefore, it is an object of the present invention to provide animproved well drilling and completion composition.

It is another object of this invention to provide an improved welldrilling and completion composition which is stable regardless of anyenvironmental contaminants.

Still other objects will be apparent to those skilled in the art fromthe following description of this invention.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with the present invention, a well drilling and completioncomposition, which has unexpected control of rheology and fluid losscontrol characteristics when employed to a water base drilling fluid, isobtained by mixing a homopolymer or copolymers of hydroxyalkylacrylateswith monomers such as acrylic acid, methacrylic acid, other alkylacrylic acids, their esters and salts, and an accelerator catalyst.Suitable comonomers for alliance with the monomers include, but are notlimited to, vinyl acetate, acrylonitrile, methylacrylate, and the like.

In a preferred embodiment of the present invention, for each barrel ofwater base drilling fluid, the composition comprises between about 0.10and about 10 quarts of the accelerator catalyst, and between about 0.10and about 6 lbs. of a potassium salt of a copolymer having a monomerwith the formula CH₂ ═CR₁ --COOH wherein R₁ is selected from the groupconsisting of H, and alkyl(s) having 1 to 4 carbon atoms, and acomonomer having the formula CH₂ ═CH--COOR₂ wherein R₂ is selected fromthe group consisting of alkyl and hydroxylalkyl, each having 1 to 4carbon atoms. More preferably, the monomer is acrylic acid wherein R₁ isH, and the comonomer is hydroxypropylacrylate wherein R₂ ishydroxypropyl.

The monomer and comonomer have a molar ratio of monomer to comonomer ofbetween about 1:1 to about 3:1. In the preferred embodiment of theinvention where the monomer is acrylic acid and the comonomer ishydroxypropylacrylate, the preferred molar ratio of the monomer (acrylicacid) to comonomer (hydroxypropylacrylate) is approximately 2:1.

The copolymer of this invention has a weight average molecular weight ofless than about 20,000, and more preferably between about 1,000 to about8,000. In the use of acrylic acid and hydroxypropylacrylate as themonomer and comonomer, respectively, the weight average molecular weightis preferably about 3,000.

The accelerator catalyst of this invention comprises water, lignite,KOH, sulfonated polystyrene, and, if the drilling fluid system is at atemperature between 285° F. to about 500° F., avinylsulfonate/vinylamide polymer. In a preferred embodiment of theinvention, the accelerator catalyst having water comprises per each bbl.of water; at least 10 to 80 lbs. of KOH (preferably 40); 25 to 50 lbs.of lignite; and 1 to 10 lbs. of sulfonated polystyrene (preferably 5lbs.). If the temperature of the drilling fluid system is between 285°F. to about 500° F., the accelerator catalyst additionally comprises 1to 10 lbs. of the vinylsulfonate/vinylamide polymer (preferably 5 lbs.).The KOH, lignite, and the polystyrene are admixed proportionately into apredetermined amount of water. The vinylsulfonate/vinylamide polymer maybe admixed with the other constituents into the accelerator catalystwater, or, optionally, the vinylsulfonate/vinylamide polymer may beadded into the drilling fluid system only after the drilling fluidsystem has reached a temperature of 285° F. or above. The catalystmixture has to be heated and stirred for a predetermined time period inorder to produce the accelerator catalyst of this invention. I havediscovered that after the exothermic reaction between the KOH, ligniteand the other product(s), the mixture should be heated to at least 120°F. (preferably 190°-212° F.) while simultaneously stirring for at least30 minutes (preferably 1.5 to 2 hours). Heating and stirring may beconducted at atmospheric conditions with a heat probe or the like. Themixture, after being heated and stirred, is subsequently centrifuged toremove any solids, and packaged as a liquid. The resulting compound,from being heated and stirred for a certain time period, acts as acatalyst with any polymeric drilling fluid additive (preferably thepotassium polyacrylate polymer) and as a very slow degeneratingcompound. The resulting catalytic compound improves the release in thefree non-bonded state the potassium ion, which is available for thenegative ionic functions of the borehole clays.

The lignite employed in the catalyst of the present invention may be anylignite or brown coal of a variety of coal intermediate between peat andbituminous coal. The chemical composition and characteristic of lignitehave been described in literature, for example Encyclopedia of ChemicalTechnology, Volume 14, Kirk-Othmer, and the Journal of American ChemicalSociety, Volume 69 (1947). Lignite has often been referred to "browncoal", or "wood coal" since the texture of the original wood isdistinct.

The Encyclopedia of Chemical Technology (Vol. 14) by Kirk-Othmer pointsout that lignite is distinguishable from lignin. Lignosulfonatematerials are prepared from lignin and does not render the improved,unexpected results obtained by this invention through the use of lignitein combination with KOH, the sulfonated polystyrene, and thevinylsulfonate/vinylamide polymer at a temperature above 285° F. Ligninis a complex noncarbohydrate constituent obtained from wood, straw, cornstocks, or the like, and is substantially different chemically from thecoal matter, lignite.

The lignitic material of this invention preferably contains appreciablequantities of humic acids. The richest common source of humic acid isthe coal known as leonardite, which is a black carbonaceous form oflignite. It is a form of oxidized lignite consisting mainly of humicacid. Natural leonardite, which normally contains 20% to 50% moisturecan be used or it can be ground in an impact mill and dried to less than20% moisture. Leonardite in its natural form is insoluble in water butis soluble in alkaline solutions. Water-soluble salts can be readilyproduced by treating leonardite with sufficient aqueous alkali toneutralize the acid radicals and then evaporating the solution todryness. Soluble forms of leonardite can be also produced by dissolvingleonardite in aqueous alkaline solutions, such as solutions of the KOHand water.

The lignitic material of this invention preferably contains about 30 wt.% on a dry basis of humic acid. More preferably, the lignitic materialemployed in the present invention contains from about 50 to about 65 wt.% on a dry basis of humic acid. Because of the variable nature oflignite, a precise molecular structure of lignite is unknown. Therefore,the molecular structure of the reaction product obtained by the reactionin water of lignite, KOH, the sulfonated polystyrene, and thevinylsulfonate/vinylamide polymer above a drilling fluid temperature of285° F., is unknown. But lignite (and humic) are well known to skilledartisans, and is available commercially.

As was previously mentioned, if the temperature of the drilling fluidsystem is about 285° F. or above, the accelerator catalyst additionallycomprises the vinylsulfonate/vinylamide polymer. Optionally, and as amatter of economics, the vinylsulfonate/vinylamide polymer may be addedto the accelerator catalyst (or directly into the drilling fluid system)only after the well has been drilled to a depth where the drilling fluidsystem at the bottom of the well is at a temperature of about 285° F. orabove. It should be understood that the vinylsulfonated/vinylamidepolymer may be added to the accelerator catalyst or the drilling fluidsystem below 285° F. without detrimentally affecting the otherconstituents.

The vinylsulfonate/vinylamide polymer is preferably a copolymer whosemonomers respectively have the general formulas:

    CH.sub.2 ═CHSO.sub.2 OH                                (a);

and

    CH.sub.2 ═CHCONH.sub.2                                 (b)

The vinylsulfonate/vinylamide polymer has an average molecular weight ofbetween 500,000 to about 4 million. The molar ratio of thevinylsulfonate monomer to the vinylamide monomer within the copolymer isbetween about 10:1 to about 1:10.

The accelerator catalyst of this invention additionally comprises apolystyrene salt which may be any non-sodium polystyrene salt but ispreferably a potassium salt of a polymer of a styrene-containing acid.More preferably, the polystyrene salt may be the potassium salt ofsulfonated polystyrene, or the potassium salt of a polystyrenecarboxylic acid.

In a preferred embodiment of the present invention, the polystyrene saltin the accelerator catalyst comprises a sulfonated homopolymer(polystyrene) whose monomer has the general formula ##STR1## having anaverage molecular weight of between 1 to 12 million, preferably 6million, with the degree of sulfonation being theoretically 100%.

The sulfonation reaction for polystyrene of this invention may beconducted in an alkaline reaction medium which can be any conventionalmedium known in the art and which is substantially inert to thesulfonation reaction. Water is a commonly used medium althoughnonaqueous media can be employed where the lignite contains sufficientabsorbed water for the reaction.

The sulfonate radical donors for the polystyrene of this inventioninclude both sulfites and bisulfites of the alkali metals and alkalineearth metals as defined hereinabove, as well as sulfurous acid andsulfur dioxide. Preferred donors include, without limitation, thesulfites and metabisulfites of potassium, calcium, magnesium, lithium,and ammonium. Sulfurous acid can also be added to the alkaline reactionsystem and similar results are achieved by the addition of sulfurdioxide gas to the alkaline reaction medium. Other common sulfonatingagents may include, but are not limited to, concentrated sulfuric acid,fuming sulfuric acid, alkali disulfates, sulfur trioxide, pyrosulfates,chlorosulfonic acid and a mixture of manganese dioxide and sulfurousacid.

The amount of sulfonate radical donor or donors will also vary widelydepending upon the degree of sulfonation desired. Sufficient sulfonatedonor should be added to effectively form a stable sulfonated product.Generally, at least about 5 parts, preferably from about 5 to about 50parts, of sulfonate radical donor or donors can be employed based uponthe total weight of the styrene to be reacted.

The varying degrees of sulfonation obtained depend in part on the wellknown ranges of conditions involved in the different methods ofsulfonation. The chemical formula for the sulfonic acid group is--SO₃ H,in which the sulfur atom is combined directly with the carbon atom inthe styrene. The sulfonate sulfur (sulfur combined directly with carbon)is quite stable and not readily removed from the styrene. The extent ofsulfonation will vary widely but will generally be that which promotesthe fluid loss control characteristics of the polystyrene.

The sulfonation reaction can be carried out at substantially anytemperature including ambient and subambient, but proceeds best atelevated temperatures, preferably from about 175° to about 480° F. fortime periods of from about 2 to about 8 hours. The reaction pressure canbe ambient or subambient but again the reaction proceeds better atelevated pressures such as from about 50 to about 800 p.s.i.g.

The drilling fluids to which the compositions of this invention can beadded may contain an effective viscosifying amount of conventionalclays. Generally, from about 1 about 20 weight percent clay can beemployed but this will vary widely depending upon the functional desiresfor the final drilling fluid and the clays employed. Suitable claysinclude kaolins (kaolinite, halloysite, dickite, nacrite, andendellite), bentonites (montmorillonite, beidellite, nontronite,hectorite, and saponite), hydrous micas (bravaisite or illite),attapulgite, sepiolite, and the like. This composition may range from 10to 25 lbs./bbl. for the system, however, the concentration is dependentupon the mud density requirements and to some degree the holetemperature above 425° F.

The drilling fluids can also contain conventional weighting agents ineffective weighting amounts, these agents including, for example, bariumsulfate, barium carbonate, iron oxide, strontium sulfate (celestite),mixtures thereof, and the like. Weighting agents can be employed to givedrilling fluids having a final density of up to about 22 pounds per U.S.gallon. More preferably, barite is the primary weight agent and isinduced to the mud composition in varying amounts to increase the muddensity from 8.5 lbs./gal. to 19.2 lbs./gal.

Other conventional additives such as emulsifiers, fermentation controlagents, and the like may be employed if desired and so long as they aresubstantially inert to the compositions of this invention.

The liquid base for the drilling fluids of this invention issubstantially aqueous and may include a minor amount of an organicmaterial (e.g., a mineral or a hydrocarbonaceous material). The aqueousbases include fresh water (sodium chloride content of less than 1 weightpercent and/or calcium content of less than 120 parts per million) andsaline water which includes both brackish and sea water (sodium chloridecontent greater than 1 weight percent and/or calcium content greaterthan 120 parts per million). The compositions of this invention areparticularly useful in saline muds in that their dispersing and fluidloss control functions are not as adversely affected by the saltscontamination as other known additives such as the chromelignosulfonates.

All the compositions of this invention can be incorporated in thedrilling fluids by simply mixing under ambient conditions of temperatureand pressure for periods sufficient to give a substantially homogeneousmixture. The amount of composition added will vary widely depending uponthe composition of the drilling fluid itself, the composition of thecomposition or compositions themselves, the particular conditions in theparticular well to which the drilling fluid is to be added, and on andon. Generally, an amount of composition effective for at least one ofdispersing and fluid loss control is suitable. As a nonlimiting example,the drilling fluid can contain amounts of at least one composition ofthis invention of from about 0.1 to about 15 weight percent based on thetotal weight of the drilling fluid.

The drilling fluids containing the compositions of this invention can beemployed in any manner in which drilling fluids are conventionallyemployed at present. Thus, the drilling fluids can be employed in thedrilling in or completing of a well, or the working over of an alreadydrilled well. The drilling fluids containing the compositions of thisinvention can also be employed as packer fluids, and the like, all ofwhich uses are intended in this invention to fall within the scope ofthe term "drilling fluid".

My invention will be illustrated by the following set forth exampleswhich are given by way of illustration and not by any limitations. Allparameters such as concentrations, mixing proportions, temperatures,pressures, rates, compounds, etc., submitted in these examples are notto be construed to unduly limit the scope of my improved process formanufacturing metallic sulphates.

EXAMPLES Example I

Per each barrel of fresh water (or seawater) the following additiveswere mixed:

(1) 0.25 lbs. of a potassium salt of the copolymer of acrylic acid andhydroxypropylacrylate (in a 2:1 molar ratio, respectively) with anaverage molecular weight of 3,000.

(2) 15 lbs. of attaplugite (or sepiolite).

(3) 7.5 lbs. of bentonite.

(4) 8.0 lbs. of starch.

(5) 1 qt. of the accelerator catalyst having water, lignite, KOH, andsulfonated polystyrene having an average molecular weight of about 6million with the degree of sulfonation being theoretically 100%.

The accelerator catalyst was prepared by adding to a barrel of water: 40lbs. of KOH, 35 lbs. of lignite and 5 lbs. of sulfonated polystyrene.The KOH, lignite and sulfonated polystyrene were admixed in the water,heated at 200° F., and stirred for about 1.5 hours.

The drilling fluid has the following properties:

A.V. cps: 12-13

PV: 8-9

YP lbs./100 ft² : 2-4

Gels 1/4

pH: 9.5-13.5

API Fluid Loss: 5-8

Potassium: 0.2-0.5%

Hot rolled 16 hrs.--180° F.

For the drilling fluid having a Temp.: to 285° F.

The addition of a commercial hydroxyethylcellose may be added. Forfiltration control below 10 cc API, use increments of 0.25 to 1.0 lbs.per bbl.

A well was drilled and it was found that those were excellent rheologyand filtration control. The diameter of the borehole of the drilled wellremained essentially constant throughout the entire length of thedrilled hole.

Example II

"Example I" is repeated except that ingredients of the acceleratorcatalyst are not heated or stirred in the preparation of the same andgenerally at times unstable rheology phenomenon is observed.

Example III

"Example I" is repeated except that the accelerator catalyst is omittedand unstable rheology phenomenon is observed.

Example IV

"Example I" is repeated except that the sulfonated polystyrene isomitted from the accelerator catalyst and unstable filtration or varyingdiameter drill hole occurs.

Example V

Per each barrel of salt water (or fresh water):

(1) 1-5 lbs. of a potassium salt of the copolymer of acrylic acid andhydroxypropylacrylate (in a 2:1 molar ratio, respectively) with anaverage molecular weight of 3,000.

(2) 10 to 15 lbs. of attaplugite (or sepeolite).

(3) 2 to 6 quarts of accelerator catalyst having water, lignite, KOH,sulfonated polystyrene having an average molecular weight of about 6million with the degree of sulfonation being theoretically 100%, and acopolymer in a 1:1 molar ratio and an average molecular weight of about2 million, of vinylsulfonate and vinylamide.

Percentages of foregoing ingredients dependent upon mud density,temperature and nature for formation drilled.

The accelerator catalyst was prepared by adding to a barrel of water: 40lbs. of KOH, 35 lbs. of lignite, 5 lbs. of sulfonated polystyrene, and 5lbs. of vinylsulfonate/vinylamide.

A well was drilled with the drilling fluid being at a temperature of285°-500° F. and the results of "Example I" were found.

Example VI

"Example V" is repeated except that ingredients of the acceleratorcatalyst are not heated or stirred in the preparation of the same andgenerally at times unstable rheology phenomenon is observed.

Example VII

"Example V" is repeated except that the potassium salt of the copolymeris omitted and no rheology control is obtained.

Example VIII

"Example V" is repeated except that the vinylsulfonate/vinylamidecopolymer is omitted from the catalyst and loss of control of filtrationand a varying diameter drill hole occurs.

Thus, by the practice of this invention, there is provided a compositionfor a drilling fluid which is stable regardless of any environmentalcontamination. The advantages of the present composition include theability to reduce the migration of water to the shale formation, torefrain from increasing the viscosity of the drilling fluid, to improveoverall fluid rheology, and to provide shale inhibitation. Thecomposition has the required ability to bond to the edges of clayparticles in a clay dispersion and to satisfy the electrical charges,and thus disperse the particle. The bonding, coating and dispersing ofthe clay particles are such that the fluid to which the present productis added, provides a thin impermeable wall cake that effectivelydecreases water loss and prevents the hydration of permeable shaleformations. The composition permits this to be done in a way which isecologically acceptable throughout the oil and gas well drillingindustry.

While the present invention has been described herein with reference toparticular embodiments thereof, and specific examples a latitude ofmodification, various changes and substitutions are intended in theforegoing disclosure, and in some instances some features of theinvention will be employed without a corresponding use of other featureswithout departing from the scope of the invention as set forth.

I claim:
 1. A water base well drilling and completion compositioncomprising per each barrel of water base well drilling and completioncomposition:(a) from about 0.10 lbs to about 6.0 lbs of a potassium saltof a copolymer of a first compound having the formula ##STR2## whereinR₁ is selected from the group consisting of H and an alkyl having 1 to 4carbon atoms, and a second compound having the formula CH₂ ═CH--COO--R₂wherein R₂ is selected from the group consisting of an alkyl radical anda hydroxyalkyl wherein said alkyl and hydroxyalkyl each have 1 to 4carbon atoms, said first compound and said second compound are combinedin a molar ratio of from about 1:1 to about 3:1 of the first compound tothe second compound, and said copolymer has a weight average molecularweight of less than about 20,000; and (b) from about 0.10 quarts toabout 10.0 quarts of an accelerator catalyst having water, from about 10lbs to about 80 lbs of KOH per each bbl. of water, from about 25 lbs toabout 50 lbs of lignite per each bbl. of water, and from about 1.0 lbsto about 10 lbs of sulfonated polystyrene per each bbl. of water andwherein said sulfonated polystyrene has an average molecular weight offrom about 1 to about 12 million, and said accelerator catalyst havingbeen prepared by heating the mixture of water, lignite, KOH andsulfonated polystyrene to a temperature of at least 120° F. whilesimultaneously stirring for at least 30 minutes.
 2. A water base welldrilling and completion composition comprising per each barrel of waterbase well drilling and completion composition:(a) from about 0.10 lbs toabout 6.0 lbs of a potassium salt of a copolymer of a first compoundhaving the formula ##STR3## wherein R₁ is selected from the groupconsisting of H and an alkyl having 1 to 4 carbon atoms, and a secondcompound having the formula CH₂ ═CH--COO--R₂ wherein R₂ is selected fromthe group consisting of an alkyl radical and a hydroxyalkyl wherein saidalkyl and hydroxyalkyl each have 1 to 4 carbon atoms, said firstcompound and said second compound are combined in a molar ratio of fromabout 1:1 to about 3:1 of the first compound to the second compound andsaid copolymer has a weight average molecular weight of from about 1,000to about 8,000; and (b) from about 0.10 quarts to about 10.0 quarts ofan accelerator catalyst having water, from about 10 lbs to about 80 lbsof KOH per each bbl. of water, from about 25 lbs to about 50 lbs oflignite per each bbl. of water, and from about 1.0 lbs to about 10 lbsof sulfonated polystyrene per each bbl. of water and wherein saidsulfonated polystyrene has an average molecular weight of from about 1to about 12 million, and said accelerator catalyst having been preparedby heating the mixture of water, lignite, KOH and sulfonated polystyreneto a temperature of at least 120° F. while simultaneously stirring forat least 30 minutes.
 3. The well drilling and completion composition ofclaim 2 wherein said R₁ is H and R₂ is hydroxypropyl.
 4. The welldrilling and completion composition of claim 3 wherein said copolymerhas a weight average molecular weight of about 3,000, and said molarratio of the first compound to the second compound is about 2:1.
 5. Thewell drilling and completion composition of claim 2 wherein saidaccelerator catalyst comprises per each bbl. of water, 10 to 40 lbs. ofKOH, 25 to 50 lbs. of lignite, 0.30 to 3 lbs. of the sulfonatedpolystyrene.
 6. The well drilling and completion composition of claim 2wherein said sulfonated polystyrene comprises a sulfonated homopolymerwhose monomer has the general formula ##STR4## and wherein the degree ofsulfonation is theoretically about 100%.
 7. The well drilling andcompletion composition of claim 2 comprising between about 0.10 lbs. toabout 6.0 lbs. of said potassium salt of the copolymer per bbl. ofdrilling fluid.
 8. The well drilling and completion composition of claim2 or 6 additionally comprising a weighting agent and a viscosityincreasing agent.
 9. The well drilling and completion composition ofclaim 2 additionaly comprising a copolymer of vinylsulfonate andvinylamide whose monomers respectively have the general formulas CH₂═CHSO₂ OH and CH₂ ═CHCONH₂, and said copolymer has an average molecularweight of between 500,000 to about 4 million.
 10. The well drilling andcompletion composition of claim 9 wherein the molar ratio of thevinylsulfonate monomer to the vinylamide monomer is between about 10:1to about 1:10.